Closing ratio vs. Sighth ratio transmissions: what is the difference? – Jalopnik

This sounds absolutely like the setup for a joke that is only funny for a hyper -specific audience. “What is the difference between a close relationship and a wide relationship transfer? About one and a half seconds to the quarter of a mile!” Yes, that is the daddy of dad ever, but it really illustrates the most important difference between transmissions with “wide” relationships and “close” relationships.

In cars with traditional internal combustion engines, drivers must constantly balance the vehicle speed and motorcycle tire of the engine, or the revolutions per minute (RPM) where the engine makes the most torque. For example, try to start from a dead stop in the upper gear. Unless your motor has the torque of an earth model, you simply walk out. Try to stimulate highway speeds in the first gear and you will probably force the engine to turn so quickly that the valves can hit the pistons. (If you have trouble shifting that seriously, you might have to practice on one of those H-pattern Shift pennen at your desk.)

The point is that your transmission has multiple gears with different proportions, each is designed to bring your vehicle to a speed where the power band of the engine can increase and maintain the speed of the car. Even engines with wide, flat torque curves still have a Power Peak somewhere in their speed range. By giving a car a “close” ratio transmission, the engine remains closer to that capital peak at every service, which improves the gear. With a “wide” ratio transmission, RPMs can fall much more during services, so that the speed of the engine can be placed further from peak power when selecting a higher gear.

In the video above from Moore Motorsports Garage you can clearly hear the difference and see when switching a wide ratio to a transmission of a close ratio. The first-to-second shift with the wide ratio transmission sees the RPM drop from approximately 7,500 to approximately 4,250. After exchanging to a gearbox with a more advantageous gear distance, a shift from the first to a second of 7,500 rpm to a much more neighbor 5,250 rpm or something. The 0-60 time of the car also decreases from 8.87 to 7.2 seconds.

Nowadays, buyers cannot choose different transmissions with different transmission ratios in a new car. Sometimes you can opt for packages that change the final drive ratio, such as how standard C8 Corvettes have a ratio of 4.89: 1, but Z51s have 5.17: 1, but the days of sailing subjects on options for specific transmissions have disappeared. So let’s go back in time to 1967 and look at three transmissions that you could have selected on your new Chevy: the Muncie “Wide ratio” M20 and the “Close ratio” M21/M22.

For all Muncie transmissions with four gears, the upper gear was the same at 1: 1, which means that input and output levels have been rotated at the same speed. Go to the third gear and the M21/M22 would be 1.28: 1 while the M20 would be at 1.46: 1. Second gear is 1.64: 1 for M21/M22S and 1.88: 1 for M20s. The first gear is 2.20: 1 for M21/M22S and 2.52: 1 for M20s. Although it may seem as if the lower first of the M20 that would give transmission an advantage of the line, you have to take into account that someone who goes to the stronger, Whine M22 “Rock Crusher” would probably also have a lower differential ratio to compensate, and then would be able to hold that L88 427.

Close ratios are not just about RIP-Roeren gear runs. The Ford/GM 10-speed gearbox automatically that you will find in Mustangs, Camaros and F-150s has a fairly narrow gear spread, narrower, even than transmissions with fewer gears. At least in theory, this makes it possible for incredibly smooth shifts that are especially useful for maintaining control during dragging, or the worst time to shock, continue to build. The 10-speed Ford can have problems with hard shift, but this is not a mistake that they have 10 forward gears.

The many close relationships also help to improve fuel consumption. Imagine that you go uphill on such an angle that the engine cannot make enough power to maintain the speed in the upper gear. You have to shift, right? Well, if you have a few other close by to choose from, you can find optimum equipment to keep Revs low, but still produce enough torque to continue to accelerate. If the transmission relationships are too wide, the next gear may be much further away, which makes the speed when they really have to be where they really should be and waste fuel.

Of course, if you just want the closest possible proportions, you want a continuous variable transmission. It gives you an infinite number of gears that are infinitely close, which results in the smoothest possible gear and optimum proportions for fuel efficiency. The main disadvantages are everything else to them. Keeping an internal combustion engine on his capital peak during acceleration transforms what a musical, intoxicating exhaust nut could be in a drone. Are the possible performance and economy worth the damage to your soul?